Question

identify the period, block, and group in which the elements with the following electron configurations are located. 1s²2s²2p⁶3s²3p⁵

○ period_3___ block_p___ group_5___
○ period_3___ block_p___ group_7___
○ period_5___ block_s___ group_3___
○ period_7___ block_s___ group_3___

Explanation:

Step1: Determine the period

The highest - numbered shell is 3 in the electron configuration \(1s^{2}2s^{2}2p^{6}3s^{2}3p^{5}\), so the period is 3.

Step2: Determine the block

The last - filled sub - shell is \(3p\), so the block is p.

Step3: Determine the group

For p - block elements, the group number is calculated as \(10 +\) the number of electrons in the outer shell (\(ns+np\)). Here, \(n = 3\), and the number of outer - shell electrons is \(2 + 5=7\), so the group number is 7.

Answer:

Period_3__ Block_p__ Group_7__